1. Field
The present invention relates to a joy stick, which potentially could be used for operation of a crane, a game machine, etc.
2. Description of the Related Art
Conventionally, the joy sticks used for a crane, operation of a game, etc. have a bellows-like rubber bellows for closing a clearance between an operation pole and a main portion. Owing to the rubber bellows, foreign substances such as dust are prevented from falling into the main portion from the clearance.
Japanese Paten Laid-open Publication Heisei 11-161419 shows an example of such a joy stick that has a rubber bellows. The joy stick used for operation of a crane has a bellows-like rubber bellows. Since a movable range of the operation pole is wide in comparison with a central axis thereof, the movable range is insufficient only in elasticity of rubber.
The clearance between an operation pole and a main portion is closed by the rubber bellows, and dust, etc. can be prevented from entering in the main portion. Also, the movable range of operation pole can be enlarged. However, such device has a problem that the rubber bellows is torn with degradation of rubber and by hardening under low temperature.
The joy stick shown in Japanese Patent Laid-open Publication 2001-350581 has a key stem which has a spherical-surface portion. Since this portion slides, the above problem has been solved without using the rubber bellows.